Android systrace: Optimize memory dumps.

systrace/atrace_helper/jni/process_info.h

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PROCESS_INFO_H_
 #define PROCESS_INFO_H_
 
 #include <map>
-#include <memory>
 
 #include "process_memory_stats.h"
 
-// Reads various process stats and details from /proc/pid/.
-class ProcessInfo {
- public:
-  struct ThreadInfo {
-    char name[128] = {};
-  };
-  using ThreadInfoMap = std::map<int, std::unique_ptr<ThreadInfo>>;
+struct ThreadInfo {
+  int tid;
+  char name[16];
+};
 
-  // Returns true if |pid| is a process (|pid| == TGID), false if it's just a
-  // thread of another process, or if |pid| doesn't exist at all.
-  static bool IsProcess(int pid);
+struct ProcessInfo {
+  int pid;
+  bool in_kernel;
+  bool is_app;
+  char name[256];
+  char exe[256];
+  std::map<int, ThreadInfo> threads;
+};
 
-  explicit ProcessInfo(int pid);
-
-  bool ReadProcessName();
-  bool ReadThreadNames();
-  bool ReadOOMStats();
-  bool ReadPageFaultsAndCPUTimeStats();
-
-  ProcessMemoryStats* memory() { return &memory_; }
-  const ProcessMemoryStats* memory() const { return &memory_; }
-  const ThreadInfoMap* threads() const { return &threads_; }
-  const char* name() const { return name_; }
-  const char* exe() const { return exe_; }
-
-  int oom_adj() const { return oom_adj_; }
-  int oom_score_adj() const { return oom_score_adj_; }
-  int oom_score() const { return oom_score_; }
-
-  unsigned long minflt() const { return minflt_; }
-  unsigned long majflt() const { return majflt_; }
-  unsigned long utime() const { return utime_; }
-  unsigned long stime() const { return stime_; }
-  unsigned long long start_time() const { return start_time_; }
-
- private:
-  ProcessInfo(const ProcessInfo&) = delete;
-  void operator=(const ProcessInfo&) = delete;
-
-  ProcessMemoryStats memory_;
-
-  ThreadInfoMap threads_;
-  char name_[128] = {};
-  char exe_[128] = {};
-
-  int oom_adj_ = 0;
-  int oom_score_adj_ = 0;
-  int oom_score_ = 0;
-
-  unsigned long minflt_ = 0;
-  unsigned long majflt_ = 0;
-  unsigned long utime_ = 0;            // CPU time in user mode.
-  unsigned long stime_ = 0;            // CPU time in kernel mode.
-  unsigned long long start_time_ = 0;  // CPU time in kernel mode.
-
-  const int pid_;
+struct ProcessSnapshot {
+  int pid;
+  ProcessMemoryStats memory;
+  // OOM badness and tolerance (oom_adj is deprecated).
+  int oom_score;
+  int oom_score_adj;
+  // Page faults.
+  unsigned long minor_faults;
+  unsigned long major_faults;
+  // Time spent in userspace and in the kernel.
+  unsigned long utime;
+  unsigned long stime;
 };
 
 #endif  // PROCESS_INFO_H_